Multistage Exhumation in the Catchment of the Anninghe River in the SE Tibetan Plateau: Insights From Both Detrital Thermochronology and Topographic Analysis

Abstract The roles of lower‐crustal flow and upper‐crustal shortening on the growth of the SE Tibetan Plateau remain under debate, which calls for a knowledge about regional exhumation history. We analyzed apatite fission track ages of modern sediments from both the east and west sub‐catchments along the Anninghe River, in the SE plateau. We obtained four age components, with peaks a bit younger in the east than in the west. Combing the asymmetric topography with higher relief in the east, we concluded a non‐uniform exhumation pattern. The components are at the Oligocene, late‐Miocene, Pliocene, and Pleistocene, mostly consistent with the timing for changes in catchment‐wide erosion rates as indicated by the inverse erosion history. We concluded that, in addition to the late‐Miocene lower‐crustal flow and Oligocene upper‐crustal shortening, the landscape in the SE plateau might also be under influences of fault strike‐slip transfer and drainage network reorganization.